Gear rack for a track of suspended or overhead conveyors

ABSTRACT

A gear rack arrangement for the track of an overhead conveyor system in which the movement of the transport unit is undertaken through the agency of a gear rack and pinion drive. The drive pinion of the transport unit meshes with the gear rack arranged at the track. According to an important aspect of the invention, the teeth of the gear rack are designed such that their thickness radially reduces inwardly and outwardly at the track curves, the plane of which is situated parallel to the plane of the gear rack.

United States Patent Inventor Eugen Schurch Gerlalingen, SwitzerlandAppl. No. 40,194

Filed May 25, 1970 Patented Jan. 1 1, 1972 Assignee Von Roll AGGerlafinger, Switzerland Priority May 28, 1969 Switzerland 8083/69 GEARRACK FOR A TRACK 0F SUSPENDED OR OVERHEAD CONVEYORS 6 Claims, 7 DrawingFigs.

0.8. CI 74/415, 74/422, 74/462 Int. Cl. Fl6h 1/06, F16h 1/04, Fl6h 55/06Field of Search 74/415,

[56] References Cited UNITED STATES PATENTS 2,974,534 3/1961 Clickner74/457 X 574,195 12/1896 Cottrell 74/460 3,490,306 1/1970 Hansgen et a1.74/415 X 2,141,627 12/1938 Street 74/462 X 2,963,103 12/1960 Wood,.lr.et al.... 74/415 X 3,184,988 5/1965 Osplack et a1. 74/462 X PrimaryExaminer- Leonard H. Gerin Attorney-Werner W. Kleeman ABSTRACT: A gearrack arrangement for the track of an overhead conveyor system in whichthe movement of the transport unit is undertaken through the agency of agear rack and pinion drive. The drive pinion of the transport unitmeshes with the gear rack arranged at the track. According to animportant aspect of the invention, the teeth of the gear rack aredesigned such that their thickness radially reduces inwardly andoutwardly at the track curves, the plane of which is situated parallelto the plane of the gear rack.

PATENTEU JAN! 1 I972 Fig. I

ATTORNEY GEAR RACK FOR A TRACK OF SUSPENDED OR OVERHEAD CONVEYORSBACKGROUND OF THE INVENTION The present invention relates to an improvedgear rack for a track of overhead or suspended conveyor systems in whichthe movement of the transport or conveying units occurs through theagency of a rack and pinion drive, the drive pinion of the transport orconveying unit meshing with the gear rack of the track.

Overhead or suspended conveyor systems are already known to the artwherein the individual conveying ortransport units with their travellingrollers run upon the travel path of the track, whereas for instance agear rack is arranged at the underside of the track also laterallythereto and with which the drive pinion of the drive arrangement for thetransport unit meshes. Such rack and pinion drive can be used both withhorizontally as well as vertically disposed track rails and furthermorealso with vertically arranged curves where the tooth profile can beaccommodated to the convex or concave configuration of the track rail.

A major drawback of the known overhead conveyor system resides in thefact that up to now it was not possible to equip horizontal curves witha gear rack. This was because teeth meshing conditions existed betweenthe gear rack and the pinion which no longer ensured for a clean rollingoff of the teeth. The rack had to essentially possess a bevel gearlikeappearance, whereas the pinion remained unchanged, so that its parallelteeth were unable to cleanly and positively mesh with the bevel gearlikerack.

SUMMARY OF THE INVENTION Therefore, there is a real need in the art foran improved gear rack for the tracks of overhead conveyor systems whichdoes not exhibit the aforementioned disadvantages associated with theprior art constructions. A primary objective of this invention is tothus provide such improved gear rack arrangement which effectivelyfulfills this need.

Another, more specific object of the present invention relates to animproved gear rack arrangement for the track of overhead or suspendedconveying systems wherein the rack and pinion drive provided for themovement of the conveying or transport units permits an engagementbetween the drive pinion and the rack which is devoid of binding orconstraint and nonetheless enables the use of a drive pinion possessingparallel teeth.

Now, in order to implement these and still further objects of theinvention, which will become more readily apparent as the descriptionproceeds, the gear rack arrangement of the present invention isgenerally manifested by the features that the teeth of the gear rackreduce in their thickness radially inwardly and outwardly at the trackcurves the plane of which is disposed substantially parallel to the gearrack plane. Under the expression the plane of the track curve" there isto be understood that plane in which the curve is situated and which,for instance, can be a vertical or horizontal plane. The gear rack planeis, for instance, the plane in which there is located the root of theteeth for standard gear teeth or for a pin gearing the plane where thereare located the radial axes of the teeth of the rack.

The teeth can be advantageously constructed as truncated cones, the axesof which extend perpendicular to the plane of the curve, and wherein thetruncated cones are constructed to possess a substantially circularcross-sectional configuration. Furthermore, the truncated cones canpossess a cross section of elipticallike configuration with the majoraxis extending radially with respect to the center of the track curve.

In the event that, for instance a pin gearing is provided for the gearrack arrangement which is used, then the teeth of the gear rack can besubstantially barrel shaped with radially directed axes extendingsubstantially parallel to the plane of the track curve, or such pins canalso possess substantially ball or spherical configuration.

BRIEF DESCRIPTIONOF THE DRAWING The invention will be better understoodand objects other than those set forth above will become apparent whencon sideration is given to the following detailed description thereof.Such description makes reference to the annexed drawings wherein:

FIG. 1 is a schematic side view, partially in section, takensubstantially along the line' I-I of FIG. 2, of a first embodiment ofgear rack used for horizontal curves;

FIG. 2 is a top plan view of the gear rack depicted in FIG. 1;

FIG. 3 is a top plan view'of a further embodiment of gear rack employedfor horizontal curves;

FIG. 4 is a fragmentary top plan view of a gear rack employing pingearing;

FIG. 5 is a cross-sectional view of the pin gearing gear rack of FIG. 4,taken substantially along the line V-V thereof.

FIG. 6 is a fragmentaryschematic top plan view of a gear rack, somewhatsimilar to the showing of FIG. 3, and illustrating more clearly theelipticallike cross-sectional configuration of the substantiallytruncated cone teeth thereof; and

FIG. 7 is a fragmentary top plan view of a gear rack employing pingearing, substantially similar to the showing of FIG. 4, andillustrating the substantially spherical configuration of the teeththereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now thedrawings, in FIGS. 1 and 2 there is illustrated a gear rack arrangementdesigned according to the teachings of the present invention whichconsists of a curved tooth support girder or member 1 formed of steel orsome other suitable material, possessing in cross section asubstantially flat rectangular profile. A number of bores or apertures 2are provided at the rack teeth support I which are spaced from oneanother at a distance corresponding to the division or spacing of theteeth of the gear rack-,pinion-drive arrangement. The teeth 10 of thecurved gear rack support member I, which teeth possess the configurationof a truncated cone 3, are mounted by means of their associatedcylindrical pins 4 in these bores 2. Now, in the embodimentshown thebase track rail defined by the teeth support girder land also the root10a of each of the teeth 10 are disposed parallel to the previouslymentioned'and defined plane of the track curve. Attachment of thetruncated cones 3, which in the exemplary case under considerationpossess a substantially circular conelike configuration, can beundertaken in any number of different ways, for instance by providing apress fit, by welding at the rear face or by an adhesive bond, or thelike. The truncated cones 3 and the base rail or support 1 can also beformed from one and the same piece, in other words as an integral unit.Further, in side view the truncated cones 3 possess the same toothprofile as the gear rack at the straight or linear-portions of the trackrail.

Now in the arrangement of gear rack depicted in FIG. 3 the tooth supportgirder or member 30 is equipped with gear teeth 11 which likewisepossess the shape of truncated cones, but in their cross-sectionalconfiguration as viewed in cross-sectional surfaces taken parallel tothe plane ofxthe'track curve here they are not circular as was the casewith the teeth [0 of FIGS. 1 and 2, rather possess a substantiallyellipticallike cross-sectional configuration, wherein the major axisextends radially with respect to thecenter of the track curve. FIG. 6similarly showsan arrangement of tooth support girder or member 20having the gear teeth 21 possessing a substantiallyellipticallikecross-sectional configuration, with the major axis thereof directedsubstantially radially withrespect to the center of the track curve.Reference numeral il2of FIG. 3 designates the parallel-teeth drivepinion meshing with the teeth 11 of the herein disclosed gear rackarrangement. The central portion 13 of this drive pinion .12, which inthe curves of the track rolls upon the teeth 11 of the gear rackarrangement, can be formed of a different material than both of theouter portions I4 and 15 of .this drive pinion 12. For instance, therecan be used as the material for the central portion [3 of the drivepinion 12, for instance a synthetic material, plastic, nylon, and soforth, in order to therefore simultaneously achieve sound dampeningeffect. In the case of highly loaded suspended or overhead conveyorsystems it can be necessary to form the central portion 13 from a harderand more wear-resistant material than the external portions 14 and 15 ofthe pinion 12.

In analogous manner, it is equally possible to use instead of truncatedcones other teeth configurations. Thus, if as in the case of FIGS. 4 and5, there is employed a pin or mangle gearing, wherein at the lineartrack portions the teeth of the gear rack arrangement are defined bycylindrical pins, then in a track curve these pins are replaced by pinmembers 17 pos sessing a sphericalor barrel-shaped pin configuration asbest shown in these FIGS. 4, and 7. The barrel-shaped pin configurationis illustrated by the pin members 17 of FIGS. 4 and 5, whereas thespherical-shaped pin configuration is illustrated by the pin members 27of FIG. 7.

By virtue of the described configuration of the teeth of the gear rackarrangement it is now possible to obtain a faultless meshing between thedrive pinion of the transport unit and the gear rack. in so doing,notwithstanding the theoretical point contact there need not be fearedin any way overloading of the teeth since, during horizontal movement,practically only the frictional resistance need be overcome and,therefore, loading of the teeth is small. On the other hand, because ofthe occurring loads in the vertical track rails it is necessary toappropriately accommodate the design of the drive pinion and the widthof the gear rack. Even if the engagement or meshing zone of the pinionshould not be completely effective in the horizontal curves, then suchcan be easily compensated by providing a somewhat wider dimensioning ofthe outer portions 14 and of the drive pinion 12.

By virtue of the described measures for designing and constructing thegear rack in the curved portions of the track conveying system it is nowpossible to construct overhead conveyors in which there can be attaineda continuous rack and pinion drive independent of the course of thetrack rails.

While there is shown and described present preferred embodiment of theinvention, it is to be distinctly understood that the inventionis notlimited thereto but maybe otherwise variously embodied and practicedwithin the scope of the following claims.

Accordingly, What is claimed is: 1

l. A gear rack arrangement for the track of an overhead conveyor systemhaving transport units moved through the agency of a gear rack andpinion drive, wherein the drive pinion of the transport unit meshes withthe gear rack arrangement at the track, the improvement comprising theprovision of teeth for such gear rack which reduce in their thicknessradially inwardly and outwardly and form steadily curved surfaces atthose track curves the plane of curvature of which is disposedsubstantially parallel to the plane of the gear rack.

2. A gear rack arrangement for the track of an overhead conveyor systemhaving transport units moved. through the agency of a gear rack andpinion drive, wherein the drive pinion of the transport unit meshes withthe gear rack arranged at the track, the improvement comprising theprovision of teeth for such gear rack which reduce in their thicknessradially inwardly and outwardly at those track curves the plane of whichis disposed substantially parallel to the plane of the gear rack, saidteeth of the gear rack comprising truncated cones the respectivelengthwise axis of which are each arranged substantially perpendicularto the plane of the track curve.

3. A gear rack arrangement as defined in claim 2, wherein each of saidtruncated cones possesses a substantially circular cross-sectionalconfiguration.

4. A gear rack arrangement as defined in claim 2, wherein each of saidtruncated cones possesses a substantially ellipticallike cross-sectionalconfiguration, wherein the major axis thereof is directed substantiallyradially with respect to the center of the track curve.

5. A gear rack arrangement as defined in claim 1, wherein

1. A gear rack arrangement for the track of an overhead conveyor systemhaving transport units moved through the agency of a gear rack andpinion drive, wherein the drive pinion of the Transport unit meshes withthe gear rack arrangement at the track, the improvement comprising theprovision of teeth for such gear rack which reduce in their thicknessradially inwardly and outwardly and form steadily curved surfaces atthose track curves the plane of curvature of which is disposedsubstantially parallel to the plane of the gear rack.
 2. A gear rackarrangement for the track of an overhead conveyor system havingtransport units moved through the agency of a gear rack and piniondrive, wherein the drive pinion of the transport unit meshes with thegear rack arranged at the track, the improvement comprising theprovision of teeth for such gear rack which reduce in their thicknessradially inwardly and outwardly at those track curves the plane of whichis disposed substantially parallel to the plane of the gear rack, saidteeth of the gear rack comprising truncated cones the respectivelengthwise axis of which are each arranged substantially perpendicularto the plane of the track curve.
 3. A gear rack arrangement as definedin claim 2, wherein each of said truncated cones possesses asubstantially circular cross-sectional configuration.
 4. A gear rackarrangement as defined in claim 2, wherein each of said truncated conespossesses a substantially ellipticallike cross-sectional configuration,wherein the major axis thereof is directed substantially radially withrespect to the center of the track curve.
 5. A gear rack arrangement asdefined in claim 1, wherein said gear rack defines a pin gearing, theteeth of which possess a substantially barrellike configuration, withthe lengthwise axis of each such tooth extending substantially parallelto the plane of the track curve.
 6. A gear rack arrangement as definedin claim 1, wherein said gear rack defines pin gearing, the teeth ofwhich each possess a substantially spherical configuration.